Risk factors and early outcomes of patients with symptomatic distal vs. proximal deep-vein thrombosis

Abstract

Isolated distal deep-vein thrombosis (iDDVT) is a distal deep-vein thrombosis (DVT) without proximal DVT or pulmonary embolism. Although its clinical significance is uncertain, its prevalence is increasing with the use of whole leg compression ultrasonography. Epidemiological data giving reported rates of venous thromboembolism (VTE) are scarce, and there is potential conflict regarding the need to treat with anticoagulant drugs. Therefore, iDDVT management varies widely from one country/physician to another. Data are available from two large multicenter observational studies of iDDVT and proximal DVT without pulmonary embolism (iPDVT), comparing risk factor profiles and early prognosis, and also from clinical trials on iDDVT. iDDVT and iPDVT differ in terms of risk factor profile, iPDVT being more associated with chronic risk factors and iDDVT with transient ones. In the short term, case fatality rates associated with iDDVT suggest that it is a clinically relevant entity and should at least be diagnosed. From a therapeutic point of view, differences in population profile and outcomes between iPDVT and iDDVT, and results from recent clinical trials in favor of a modest VTE potential of iDDVT indicate that specific randomized double-blind trials are necessary to determine an appropriate and accepted mode of care for iDDVT.